Crew incapacitation actions are writen in the FCTM and the FCOM 3. (this for the airbus)
Basically, you have to take over pressing the red push botton on the side-stick 45seconds. Return to the safe flight and engage the A/P (your side).
Then, "purser to cockpit please" by the PA, ask her/him to fasten the seat belt and move the seat backwards (so as to not to interfere in the instruments or with the handling of the aircraft). In addition ask for any qualified pilot on board and a doctor.
Declare emergency,In the mean time, in the MCDU you have an option which is called closest airports, with the information of the four nearest airport around you (check on the maps/charts the suitable, runway length...).
If you donīt have the last weather report ask for it, request proceed to, priority, high speed, radar vectors..
Well, a good idea would be inform the passengers (I wouldnīt say the real problem at all..)
When approaching, inform to the ATC that you are going to stop the aircraft on the rwy and medical assistance is required(giving all the details about the incapacitated crew)
Prepare the approach and read the check list earlier than usual. Request radar vectoring and prefer a long approach to reduce work load.
if both are incapacitated,,,just pray or sing a song untill run out of fuel.
bye